This is a companion discussion topic for the original entry at https://www.rstudio.com/blog/first-bookdown-contest
Since the release of the bookdown package in 2016, there have been a large number of books written and published with bookdown. Currently there are about 200 books (including tutorials and notes) listed on bookdown.org alone! We have also heard about other applications of bookdown based on custom templates (e.g., dissertations).
As popular as bookdown is becoming, especially with teachers, researchers, and students, we know it can take a lot of time to tailor bookdown to meet the special typesetting requirements of your institution or publisher.